The present invention concerns a powder paint system that includes an arrangement permitting quick color change and that minimizes paint lost when making the color change.
Colored powder paint must be completely purged from a paint line and spray gun, particularly when changing from a dark color to a light color, so that residue paint from the previous color does not discolor the next color. A problem is that this leads to slow cycle times, wasted labor, and process inefficiencies. Also, existing purge methods lead to considerable waste in the form of purged material that must be landfilled, which could be very expensive, particularly if the landfilled materials are potential pollutants to the environment.
Some manufacturers have chosen to use a different paint line and spray gun for each color. However, this requires a large capital expenditure for equipment. Further, the equipment takes up space and each station requires constant maintenance and upkeep, whether or not it is used.
Another problem is that the particles of the powder paint will degrade if kept in a fluidized state ready for use over long periods of time. Powder paints must be fluidized (i.e., suspended in air or a gaseous carrier), so that a uniform and steady flow of particles of powder paint can be picked up and carried to a part upon demand. Degradation occurs because collisions between particles affect the particle surfaces and also cause the particles to become smaller in size. Where a high voltage charge is used to assist in depositing the powder paint onto a part, the degraded powder materials have a reduced ability to pick up or hold a high voltage charge.
Therefore, an apparatus and method solving the aforementioned problems and having the aforementioned advantages is needed.